Humidifier tank



FIG. 1 is a top front perspective view of a humidifier tank;

FIG. 2 is a bottom rear perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a right side elevational view thereof; and,

FIG. 8 is a left side elevational view thereof.

The broken line showing of environmental structure in FIGS. 1-8 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a humidifier tank, as shown and described. 